In Artisan's Way, there is a well between the Alchemy Workshop and R&T's Sundries where you can draw up to five units of water at a time, as many times as desired. You can then sell the water for 1 Cole each at any of the shops; R&T's Sundries is immediately to the right of the well. If you have the patience and time, you can earn an unlimited amount of Cole by gathering and selling the water from the well. While not an extremely fast method of earning money, it is easy and will not advance the date. If you need some Cole to purchase materials for alchemy and do not wish to use up materials for quests or waste days by going out and gathering elsewhere, this is the way to do it.